move some io related utils to pkg/ioutils

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
pkg/ioutils: add WriteCloserWrapper

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
pkg/ioutils: add NewBufReaderWithDrainbufAndBuffer

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
pkg/ioutils: add ReaderErrWrapper to readers

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
pkg/pool: add pools for bufio readers & writers

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
archive: use pooled bufio readers and writers

Docker-DCO-1.1-Signed-off-by: Cristian Staretu <cristian.staretu@gmail.com> (github: unclejack)
fix typos in error messages

Signed-off-by: Ward Vandewege <ward@jhvc.com> (github: cure)